Experimental investigation of high velocity impact response of CFRP laminates subjected to flyer plate impact

Abstract

Carbon fiber reinforced plastic (CFRP) composites are widely used in aircraft and automotive industries due to their extremely high specific strength and stiffness. High velocity impact is inevitable throughout the service life of composite structure and it is important to understand its impact response. In this study, high velocity impact response of CFRP laminates subjected to flyer plate impact were investigated in the velocity range of 32∼100 m/s by a gas gun coupled with 3D Digital Image Correlation (DIC) analysis. For comparison purposes, similar tests were carried out on 2A12 aluminum alloy plates of equivalent thickness. The PVDF pressure sensor was used to measure the impact pressure of the target plate, and the influence of impact velocity and target type on the impact pressure was analyzed. The damage and failure mechanism of CFRP laminates during impact were analyzed by digital microscope, ultrasonic C-scan and sectional image. The results show that the variation trend of the theoretical impact pressure is consistent with that of the experimental impact pressure, and the experimental impact pressure is smaller than the theoretical impact pressure. The damage and failure mechanism of two target plates are different under high velocity impact. For 2A12 plate, a truncated circular cone-shape bulge is generated on the 2A12 plate and this damage patterns appears regardless of the impact velocity. For CFRP laminates, impact indentation with elongated splits extending from the indentation edges is observed on the impacted surface of the target plate. The delamination zone of the adjacent layers is distributed in a fan-shaped area and the delamination direction is consistent with the direction of the fibers in the front ply. The data from the experiments can be used to evaluate and refine composite material models and computational methodologies that are used to predict the impact response of composite.